KR101779889B1

KR101779889B1 - Composite membrane comprising polyamide coating layer and preparation method thereof

Info

Publication number: KR101779889B1
Application number: KR1020150053070A
Authority: KR
Inventors: 김인철; 송두현; 장한나; 이혜진; 안은숙; 최진일
Original assignee: 한국화학연구원
Priority date: 2015-04-15
Filing date: 2015-04-15
Publication date: 2017-09-20
Also published as: KR20160123425A

Abstract

The present invention relates to a composite membrane comprising a polyamide coating layer and a method for producing the same, and a method for producing the same, which comprises performing polyamide interface polymerization on the surface of a porous polymer scaffold having macropores having an average pore size of 0.1 m or more, By using polyethyleneimine having a number average molecular weight of 800 to 80,000 as an amine compound for forming a polyamide (first monomer) in the formation of the coating layer, the polyamide coating layer can be formed more uniformly and efficiently to reduce the pore size, It is possible to provide a composite membrane which does not decrease the permeability.

Description

TECHNICAL FIELD The present invention relates to a composite membrane comprising a polyamide coating layer and a preparation method thereof,

The present invention relates to a composite membrane comprising a polyamide coating layer and a method for producing the same.

Due to the gradual decrease in line width used in semiconductor processes, the removal of impurities in photoresist solutions is becoming increasingly important. If the impurity removal is not performed, the pattern will be defective. The impurities are mainly composed of two kinds: hard particles, which are metal particles, and gel particles or soft particles, which are agglomerates of polymers and metals. Currently commercially available membranes are manufactured using a polar material and have a limitation in reducing pores and insufficient removal of impurities.

On the other hand, the interfacial polymerization method is a method in which a monomer capable of polymerizing with each other is added to a solvent that does not mix with each other to synthesize a polymer as a reaction occurs at the interface. Interfacial polymerization for forming a coating layer of a polyamide is performed by dissolving an amine compound and an acid halide compound as monomers in a solvent which is not mixed with each other and then bringing the respective monomer solutions into contact with each other to cause a polymerization reaction at the interface, The support is immersed in an aqueous solution containing an amine compound as a first monomer and then immersed in an organic solution containing a second monomer capable of forming a polyamide by polymerization with the first monomer to form a polymerization reaction at the interface of the porous polymer scaffold .

As a method of manufacturing membranes that do not significantly reduce the permeation flow rate while reducing the conventional pores, polyamide coatings using interfacial polymerization were used. Such a polyamide interfacial polymerization method is very important in the property of the support, and a hydrophobic support such as polysulfone is generally used to coat the support. Hydrophilic supports have difficulty in coating. Also, when a monomer is used, the pore size of the support is important, so that when the pore is large, the coating tends not to be properly performed.

It is an object of the present invention to provide a method for producing a composite membrane which does not significantly reduce the permeation flow rate while reducing pores by interfacial polymerization on a porous support having a large pore to form a composite polyamide coating layer and a membrane prepared therefrom and the use of the membrane .

According to a first aspect of the present invention, there is provided a porous polymer scaffold comprising: a first step of preparing a porous polymer scaffold having an average pore size of 0.1 탆 or more; A second step of immersing the porous polymer scaffold as an aqueous solution containing polyethyleneimine having a number average molecular weight of 800 to 80,000 as a first monomer for polyamide formation; And a third step of polymerizing the porous polymer scaffold with the first monomer to form a polyamide-based coating layer by interfacial polymerization by immersing the porous polymer scaffold in an organic solution containing a second monomer that forms a polyamide by polymerization with the first monomer. And a manufacturing method thereof.

A second aspect of the present invention relates to a porous support having an average pore size of 0.1 탆 or more; And a polyamide coating layer formed by interfacial polymerization of polyethyleneimine having a number average molecular weight of 800 to 80,000 and a polyfunctional acid halide compound on the surface of the porous support, wherein the fractionated molecular weight is 800 to 50,000.

A third aspect of the present invention provides a water treatment apparatus comprising a composite membrane according to the second aspect.

A fourth aspect of the present invention provides a method for producing water-treated water comprising water-treating using the composite membrane according to the second aspect.

Hereinafter, the configuration of the present invention will be described in detail.

In order to provide a composite membrane which does not greatly decrease the permeation flow rate while reducing pores, the present invention provides a porous polymer scaffold which comprises a porous polymer scaffold having macropores having an average pore size of 0.1 탆 or more as the porous polymer scaffold, 1 monomers) having a number average molecular weight of 800 to 80,000.

That is, the present invention relates to a polyamide coating composition for forming a polyamide coating layer by performing polyamide interface polymerization on the surface of a porous polymer scaffold having macropores having an average pore size of 0.1 m or more, By using polyethyleneimine having a molecular weight of 800 to 80,000, the first monomer enters into the pores on the surface of the porous polymer scaffold and the first monomer is not lost on the surface of the support and the first monomer is positioned on the surface of the support, It is possible to provide a composite membrane which is efficiently subjected to interfacial polymerization with two monomers to form a polyamide coating layer more uniformly and efficiently so as to reduce pores while not significantly reducing the permeation flow rate.

Preferably, the porous polymer scaffold may have an average pore size of 0.1 mu m to 1.0 mu m. If the average pore size of the porous polymer scaffold is less than 0.1 탆, the pore size of the composite membrane after the polyamide interfacial polymerization becomes too small, and the permeation flow rate may be greatly reduced. If the average pore size is more than 1.0 탆, interfacial polymerization may be difficult.

The method for producing a composite membrane of the present invention is a method for producing a composite membrane using polyimide interfacial polymerization (polyimide polymerization) using a polyethyleneimine having a number average molecular weight of 800 to 80,000 as an amine compound (first monomer) for polyamide formation on the surface of a porous polymer scaffold having an average pore size of 0.1 m or more. To reduce the pores of the composite membrane to provide a composite membrane having a cut-off molecular weight of 800 to 50,000.

As used herein, the term "molecular weight of cut-off" refers to the size of the molecular weight that can be filtered out, and includes a spherical polymer (e.g., PEG or Protein, etc.). That is, the lower the cut-off molecular weight, the smaller the material can be separated.

Also, the method of producing a composite membrane according to the present invention is advantageous in that the pore size of the composite membrane is reduced as described above, and the permeation flow rate is not significantly reduced while decreasing the molecular weight of the fraction.

Preferably, the composite membrane prepared according to the present invention may have a water permeation flow rate of 50 to 150 L / m 2 hr at 1 kgf / cm 2.

Specifically, in the examples of the present invention, it was confirmed that the composite membrane prepared according to the present invention had a pore size significantly lower than that before the polyamide interfacial polymerization, and that the permeate flow rate was more than 50 L / m 2 hr (Table 1).

The preparation of the porous polymer scaffold of the first step can be accomplished by purchasing a commercialized porous polymer scaffold known in the art or by using a method of manufacturing porous polymer scaffolds known in the art without limitation. Preferably, the first step is a vapor-induced phase separation (VIPS), a non-solvent induced phase separation (NIPS), a thermally induced phase separation (TIPS) Or a combination thereof.

According to the steam-induced phase separation method, a polymer solution in which a polymer resin is dissolved in a good solvent is formed, and the formed polymer solution is exposed to water vapor to form a phase transition. According to the non-solvent-derived phase separation method, a polymer solution in which a polymer resin is dissolved in a good solvent is formed, and the formed polymer solution is brought into contact with a solution containing a non-solvent, And solidification is induced to produce a film. On the other hand, according to the heat-induced phase separation method, the polymer solution is prepared by forcibly dissolving the polymer resin in a poor solvent at a temperature higher than the phase separation temperature. The polymer solution is molded, and the polymer solution is contacted with a cooling liquid at a phase separation temperature or lower to coagulate the polymer solution to produce a film.

The material of the porous polymer scaffold can be formed into a porous polymer scaffold, and as long as the surface of the porous scaffold can be polyamide-interfacial polymerized, the polymer used in the production of the porous polymer scaffold known in the art can be used without limitation.

In the present invention, the porous polymer scaffold may be composed of a hydrophilic polymer. Preferably, the porous polymer scaffold may be composed of a hydrophilic polymer containing a sulfone group, an acetate group, an amide group, or a combination thereof. Specifically, the porous polymer scaffold may be made of polyethersulfone, cellulose acetate, polyamide, or a combination thereof.

When a porous polymer scaffold having hydrophilicity as a porous polymer scaffold is used in the conventional method, an aqueous solution containing an amine compound having a small molecular weight used as a first monomer is impregnated into the pores of the scaffold and then an organic The interfacial polymerization efficiency at the surface of the support is lowered when brought into contact with the solution. Therefore, in general, in the case of a hydrophilic polymer scaffold made of a hydrophilic polymer, it is difficult to form a polyamide coating layer by interfacial polymerization.

However, in the present invention, even when the hydrophilic polymer scaffold is immersed in the aqueous solution containing the first monomer by using polyethyleneimine having a number average molecular weight of 800 to 80,000 as the first monomer for polyamide formation, the first monomer It is possible to form the polyamide-based coating layer by effectively interfacial polymerization with the second monomer.

In one embodiment of the present invention, the porous polymer scaffold may be obtained by forming a polyethersulfone polymer solution, exposing it to water vapor, or immersing it in a non-solvent to induce phase transition. In the preparation of the polyethersulfone polymer solution, dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide and the like are used. As additives for pore formation, polyvinylpyrrolidone, polyethylene glycol Etc. may be used. The number average molecular weight of the polyvinyl pyrrolidone is 10,000 to 400,000, and the number average molecular weight of the polyethylene glycol is 200 to 200,000. The content of the polyethersulfone in the polyethersulfone polymer solution is preferably 10 to 30% by weight. If it is less than 10% by weight, the strength of the porous polymer scaffold may be weakened. If it exceeds 30% by weight, the viscosity of the porous polymer scaffold may be excessively increased. When the formed polyethersulfone film is exposed to water vapor to form the pores, the relative humidity is preferably maintained at 40 to 99%. When the relative humidity is less than 40%, pore formation is reduced.

As described above, in the second step, the porous polymer scaffold can be immersed as a first monomer for polyamide formation into an aqueous solution containing polyethyleneimine having a number average molecular weight of 800 to 80,000 to form a polyethyleneimine layer.

Preferably, the aqueous solution containing the first monomer for polyamide formation in the second step may be an aqueous solution containing the first monomer in a concentration of 1 to 5% by weight of the total aqueous solution. Most preferably, polyethyleneimine having a number average molecular weight of 60,000 can be used as the first monomer.

In the third step, the polyimide-based coating layer may be introduced through interfacial polymerization by immersing the porous polymer scaffold on which the polyethyleneimine layer obtained in the second step is formed in an organic solution containing a second monomer for polyamide formation.

In the present invention, the second monomer which forms the polyamide interface polymerization with the polyethyleneimine is preferably a polyfunctional acid halide compound. The polyfunctional acid halide compound may be, but is not limited to, a polyfunctional acyl halide, a polyfunctional sulfonyl halide, or a polyfunctional isocyanate. Preferably, the polyfunctional acid halide is selected from the group consisting of trimesoyl halide, benzophenone tetracarboxylic acid halide, trimellitic acid halide, pyromellitic acid halide, isophthalic acid halide, terephthalic acid halide, Naphthalene dicarboxylic acid halide, dicarboxylic acid halide, 1,3,5-cyclohexanetricarboxylic acid halide, 1,3-cyclohexanedicarboxylic acid halide, 1,4-cyclohexanedicarboxylic acid halide Or a mixture thereof.

Preferably, the organic solution containing the second monomer for polyamide formation in the third step may be an organic solution containing the second monomer in a concentration of 0.05 to 1% by weight in the total organic solution. As a specific embodiment, trimesoyl chloride may be used as the second monomer, and hexane may be used as a solvent of the organic solution.

For example, the interfacial polymerization may be performed by immersing the porous polymer scaffold in an aqueous solution containing the first monomer for 1 to 10 minutes, then drying for 1 to 10 minutes, immersing in the second monomer-containing organic solution for 1 to 3 minutes, Min. &Lt; / RTI >

As described above, the composite membrane according to the present invention comprises a porous support having an average pore size of 0.1 탆 or more; And a polyamide coating layer formed on the surface of the porous support by interfacial polymerization of polyethyleneimine having a number average molecular weight of 800 to 80,000 and a polyfunctional acid halide compound, wherein the fraction molecular weight is 800 to 50,000. The presence of the polyamide coating layer remarkably reduces the molecular weight of the fraction but allows the water permeation flow rate to be excellent at 50 kg / cm 2 or more, preferably 50 to 150 L / m 2 hr.

The composite membrane according to the present invention can be manufactured by the composite membrane manufacturing method according to the present invention described above.

The composite membrane according to the present invention can be used as a reverse osmosis membrane or a nanocomposite membrane.

The composite membrane according to the present invention can be applied to a water treatment apparatus, specifically, a wastewater treatment apparatus for a semiconductor process, an ultrapure water purification apparatus for a semiconductor process, a water purifier, a pretreatment apparatus for a seawater desalination process, a water softener, a water treatment apparatus, Can be used.

Also, since the composite membrane according to the present invention can have a cutoff molecular weight of 800 to 50,000, it can be used as a reverse osmosis membrane in the production of purified water, which comprises water treatment through a reverse osmosis process.

In the present invention, the water used for the water treatment may be ultrapure water, wastewater or seawater.

The method of the present invention is a method of forming a polyamide coating layer by performing polyamide interface polymerization on the surface of a porous polymer scaffold having macropores having an average pore size of 0.1 탆 or more, By using polyethyleneimine having an average molecular weight of 800 to 80,000, a polyamide coating layer can be formed more uniformly and efficiently to provide a composite membrane that does not significantly decrease the permeation flow rate while reducing pores.

FIG. 1 is a cross-sectional view of a polyethersulfone membrane manufactured according to an embodiment of the present invention by electron microscope.
FIG. 2 is a result of observation of a coated surface of a polyamide-coated membrane manufactured according to an embodiment of the present invention by an electron microscope.
FIG. 3 shows the result of observation of the coated surface of the polyamide-coated membrane prepared according to Comparative Example 2 with an electron microscope.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Production Example 1: Preparation of polyether sulfone membrane

A polymer solution having a composition of 15% by weight of polyethersulfone, 30% by weight of dimethylformamide and 55% by weight of polyethylene glycol (number average molecular weight of 600) was uniformly prepared at room temperature. The film was uniformly coated on a glass plate with a casting knife having a thickness of 200 탆, exposed to air at 80% relative humidity for 3 minutes at 20 캜, immersed in distilled water at 15 캜 for coagulation, and tested 24 hours later. When the section was observed with an electron microscope, a complete sponge-like cross-section was seen (Fig. 1). The permeate flow rate was 1500 L / ㎡ hr at 1 kgf / ㎠, the maximum pore size was 0.4 ㎛, and the average pore size was 0.2 ㎛ (Table 1).

Preparation Example 2: Preparation of polyether sulfone membrane

A polyethersulfone membrane was prepared in the same manner as in Preparation Example 1 except that the relative humidity was adjusted to 40%, and the membrane was tested. When the section was observed with an electron microscope, a complete sponge-like cross-section was observed. The permeate flow rate was 500 L / ㎡ hr at 1 kgf / ㎠, the maximum pore was 0.08 ㎛ and the average pore was 0.07 ㎛. It was confirmed that the permeation flow rate was significantly reduced as compared with that of Production Example 1 (Table 1).

Example 1: Polyamide coating Membrane Produce

To coat polyamide on the polyethersulfone membrane support prepared in Preparation Example 1, the membrane was immersed in an aqueous solution of 2% by weight of polyethyleneimine (number average molecular weight: 60,000) for 1 minute, and after removing the amine solution on the surface with a roller, And then immersed in 0.1 wt% trimesoyl chloride (solvent hexane) for 1 minute and then dried at 60 DEG C for 5 minutes to complete coating.

Comparative Example 1: Preparation of polyamide-coated membrane

A polyamide-coated membrane was prepared in the same manner as in Example 1, except that the polyethersulfone membrane support prepared in Preparation Example 2 was used.

Comparative Example 2: Polyamide coating Membrane Produce

A polyamide-coated membrane was prepared in the same manner as in Example 1, except that an amine solution containing piperazine was used instead of polyethyleneimine (number average molecular weight: 60000).

Comparative Example 3: Preparation of polyamide-coated membrane

A polyamide-coated membrane was prepared in the same manner as in Example 1, except that an amine solution containing m-phenlyene diamine was used instead of polyethyleneimine (number average molecular weight: 60000).

Example 2: Preparation of polyamide-coated membrane

A polyamide-coated membrane was prepared in the same manner as in Example 1, except that it was used as an amine solution containing polyethyleneimine (number average molecular weight 800) instead of polyethyleneimine (number average molecular weight 60000).

Example 3: Preparation of polyamide-coated membrane

A polyamide-coated membrane was prepared in the same manner as in Example 1 except that 2 wt% of polyethyleneimine (number average molecular weight 60000) was changed to 1 wt% and 0.1 wt% of trimethoyl chloride was changed to 0.05 wt%.

Example 4: Preparation of polyamide-coated membrane

A polyamide-coated membrane was prepared in the same manner as in Example 1, except that 2 wt% of polyethyleneimine (number average molecular weight 60000) was changed to 0.5 wt% and 0.1 wt% of trimethoyl chloride was changed to 0.03 wt%.

Experimental Example One: Membrane Performance evaluation

The membranes prepared in Example 1 and Comparative Example 2 (using piperazine) were observed under an electron microscope to confirm cross-sectional views of the membranes. As a result, it was confirmed that a uniform coating layer was formed on the surface of the membrane prepared in Example 1 (FIG. 2). However, the membrane of Comparative Example 2 in which a polyamide coating layer was formed using piperazine as an amine compound showed that the coating layer on the surface was not uniform and some coating layers were not completely formed (FIG. 3).

In addition, permeation fluxes of the membranes prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were measured using ultrapure water. The membrane performance is shown in Table 1 below (measured pressure, 1 kgf / cm 2). The pore size was measured using a PMI Bubble Point Tester and the results are shown in Table 1. As another method for measuring the pore size of the prepared membrane, the concentration of the undiluted solution and permeate was measured by HPLC using 1000 ppm aqueous solution of polyethylene glycol having different molecular weights and then the removal rate (R) was shown. The molecular weight of polyethylene glycol having R of 0.9 or more is shown by fractional molecular weight.

R = (Cf - Cp) / Cf

R is the removal rate, Cf is the concentration of the undiluted solution, and Cp is the concentration of the permeate.

Permeate flow rate (L / m2hr) Maximum porosity
(탆) Average porosity
(탆) Fraction molecular weight Production Example 1 1500 0.40 0.20 Example 1 55 - - 2000 Example 2 120 - - 50000 Example 3 68 - - 5000 Example 4 76 - - 10000 Production Example 2 500 0.08 0.07 Comparative Example 1 20 - - 2000 Comparative Example 2 800 - - 200000 Comparative Example 3 400 - - 100000 [Note] -: Pore size is too small to be measured.

As shown in Table 1, the porous polymer scaffold having macropores having an average pore size of 0.1 탆 or more was used as the porous polymer scaffold, and the number average molecular weight of the amine compound (first monomer) for polyamide formation was 800 To 80,000 polyethylene imine, it is possible to reduce the pores of the composite membrane to provide a superior composite membrane having a cutoff molecular weight of 50,000 or less and a permeation flow rate of 50 L / m 2 or more.

On the contrary, when the first monomer having a small molecular weight was used (Comparative Examples 2 and 3), the interfacial polymerization was not completely carried out on the surface of the support with a cut-off molecular weight of 100000 or more and the pore size did not decrease to a desired level .

Further, it was confirmed that the permeation flow rate was greatly reduced to the level of 20 L / m 2 hr in the case of using the porous polymer scaffold having a pore size smaller than 0.1 μm (Comparative Example 1).

Claims

A first step of preparing a porous hydrophilic polyethersulfone support having an average pore size of 0.1 mu m to 1.0 mu m;
A second step of immersing the porous hydrophilic polyethersulfone support in an aqueous solution containing polyethylenimine having a number average molecular weight of 800 to 80,000 as a first monomer for polyamide formation; And
And a third step of immersing the porous hydrophilic polyethersulfone support in an organic solution containing trimesoyl chloride to form a polyamide-based coating layer by interfacial polymerization,
The first step
Molding a polyethersulfone polymer solution containing 10% by weight to 30% by weight of polyethersulfone into a polyethersulfone film; And
Exposing the polyethersulfone film to water vapor at a relative humidity of greater than 40% but less than 99% to produce a porous hydrophilic polyethersulfone support having an average pore size of from 0.1 mu m to 1.0 mu m,
Wherein the water permeation flow rate is 50 to 150 L / m < 2 > hr at 1 kgf / cm < 2 >.

delete

The process for producing a composite membrane according to claim 1, wherein the prepared composite membrane has a fraction molecular weight of 800 to 50,000.

delete

8. A composite membrane produced by the process of claim 1 or 7,
A porous hydrophilic polyethersulfone support having an average pore size of 0.1 mu m to 1.0 mu m; And a polyamide coating layer formed by interfacial polymerization of polyethyleneimine having a number average molecular weight of 800 to 80,000 on the surface of the porous hydrophilic polyethersulfone support and trimethoyl chloride, wherein the fraction molecular weight is 800 to 50,000 and the water permeation flow rate is 1 kgf / Cm < 2 > at 50 to 150 L / m2 hr.

delete

A water treatment apparatus comprising the composite membrane of claim 9.

The water treatment apparatus according to claim 12, characterized by being a wastewater treatment device for semiconductor process, an ultrapure water purification device for semiconductor process, a water purifier, a pretreatment device for seawater desalination process, a water softener, a water treatment device, a wastewater treatment device or a food purification device.

A method for producing water-treated water, comprising the step of water-treating using the composite membrane of claim 9.

15. The method according to claim 14, wherein the water used for the water treatment is ultrapure water, wastewater or seawater.